Nowadays, large display screens are widely used to display information at public places such as shopping malls, name brand stores, subways, airports, etc. The large display screens typically receive the media information from playback devices, which in turn acquire the media information from removable storage devices, such as Universal Serial Bus (USB) drive, Secure Digital (SD) card, etc. Media files can be written into these storage devices with a personal computer (PC). The storage devices can be connected to the playback devices to play the media files. The storage devices can also be internal to the playback devices.
When a playback device plays a media file stored in the storage device, it may be necessary for the storage device to determine which part of the media file is being read and displayed by the playback device. For example, the storage device may need to determine a reading progress of the media file. The storage device may also need to provide some additional information about the media content that is currently being displayed to other terminal devices. For example, if the media content depicts a product, the storage device may need to provide the name of the product and the web address of a web page associated with the product.
However, typically the storage device only reads and writes the media file as data blocks, and do not have information, such as file name, that enables the storage device to identify which data block belongs to a particular media file. The file system information (e.g., file handles, file locations, other information for accessing the files, etc.) is typically available only to the operating system running on the playback device. Therefore, the storage device typically cannot determine which part of the media file is being read and displayed, and cannot provide additional information about the media content that is currently being displayed.